Abstract 1-3 piezoelectric composite material is widely applied in medical ultrasound transducers. The acoustic impedance mismatching still exists between composite materials and human tissue, this mismatching limits the performance of the 1-3 composite transducer. In this work, Parylene coating technique is employed to enhance the performance of a 1-3 piezoelectric composite transducer whose center frequency is 13 MHz. Theory and simulation analysis is carried out to estimation and optimize the influence of the Parylene coating layer. Pulse- echo experiment is performed to verify the hypothesis of theory and simulation. The experiment results confirm that the performances of the transducer are effectively enhanced by Parylene coating and the optimum thickness of the coating Parylene layer is about 39.5 μm. Compared to the uncoated 1-3 composite transducer, the echo amplitude of 39.5 μm Parylene coated transducer increases 98.8%, the value of −6 dB pulse width decreases 39.5%, the value of −20 dB pulse width decreases 22.7%, the bandwidth increases 51.9%, and the center frequency is not affected. These results prove the feasibility and effectiveness of the Parylene coating layer in transducer performance enhancement.

中文翻译：

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用于 13 MHz 1-3 复合换能器性能增强的聚对二甲苯涂层

摘要 1-3压电复合材料广泛应用于医用超声换能器。复合材料与人体组织之间仍然存在声阻抗失配，这种失配限制了1-3复合换能器的性能。在这项工作中，聚对二甲苯涂层技术被用来提高中心频率为 13 MHz 的 1-3 压电复合换能器的性能。进行理论和模拟分析以估计和优化Parylene涂层的影响。进行脉冲回波实验验证理论和仿真假设。实验结果证实，Parylene涂层有效提高了换能器的性能，Parylene涂层的最佳涂层厚度约为39.5 μm。与未镀膜的1-3复合换能器相比，39.5 μm Parylene镀膜换能器回波幅度提高98.8%，-6 dB脉宽值降低39.5%，-20 dB脉宽值降低22.7%，带宽提高51.9%，中心频率不受影响。这些结果证明了聚对二甲苯涂层在提高换能器性能方面的可行性和有效性。